Neurotransmitters and 2nd messengers

This list is primarily from Table 5.1 of Dowling's Retina.

Neurotransmitters
• Amino Acids
  • L-Aspartate
  • GABA (Gamma-Aminobutyric Acid)
  • L-Glutamate (Kainate, Quisqualate, AMPA and NMDA receptors)
  • Glycine
• Amines
  • Acetylcholine (ACh; cholinergic)
  • Dopamine
  • Epinephrine
  • Histamine
  • Norepinephrine
  • Serotonin (also called 5-hydroxytryptamine or 5-HT)
• Peptides - typically modulate response rather than create one.
  • Cholecystokinin
  • Enkephalin
  • Glucagon
  • Neurotensin
  • Neuropeptide Y
  • Somatostatin (SRIF)
  • Substance P (SP)
  • Vasoactive Intestinal peptide (VIP)

2nd messengers and other intra-neural chemicals
• adenosine 3', 5'-monophosphate (cyclic amp or cAMP)
• cAMP-dependent protein kinase (PKA or A-kinase)
• guanosine triphosphate (GTP)
• G-Proteins (GTP-binding regulatory proteins) - more than 16
  Hille, page 173 - "In the resting state, G proteins carry a bound GDP and diffuse about in the plane of the membrane. If they encounter an agonist-occupied receptor, the GDP is liberated, a GTP from the cytoplasm takes its place, and the G protein is believed to split into two mobile parts, G_alpha-GTP and G_alpha_gama. These are the activated forms of the G protein." If G_alpha-GTP encounters adenylyl cyclase int he membrane, cAMP synthesis is stimulated so long as they remain associated. Eventually however the activated G protein inactivates itself, as the G protein has a slow GTPase activity that cleaves its own bound GTP to GDP. The resulting G_alpha-GDP is inactive, and cAMP synthesis stops."
  • G_s - G stimulatory
  • G_i - G inhibitory
  • G_o - G other
  • G_p - G proteins
  • G_?
• cyclic GMP (cGMP)

Back to general retina list

576 visit(s) to this page.

Lance Hahn (lance@retina.anatomy.upenn.edu)